.menu ul > li:hover > .dropdown-menu {
visibility: hidden;  
opacity: 0;
transform: scale(0.5);
}


.menu ul > li .dropdown-menu {
visibility: hidden;
opacity: 0;
transform: scale(0.5);
transition: all .2s;
}

.menu ul > li .dropdown-menu.show {
visibility: visible;
opacity: 1;
transform: scale(1);
transition: all .2s;
}